it is a specialist music programme that needs an expert presenter - the one they have just sacked would be ideal

I completely agree with your first conclusion, but not your second. I'd say "adequate" but far from ideal. Mark Radcliffe will probably be the same, so our Honourable Friends need not get sidetracked. "Ideal" would be somebody a few decades younger with the folk equivalent of the broadcasting skills of an Andy Kershaw or Charlie Gillett. There are reasons that people like them won Sony Gold Awards, and describing every record as "cracking" and "the best ever" wasn't one of them.